Question about 2002 GMC Yukon XL

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I have a 2002 yukon xl 1500 slt 5.3 and I took it to auto zone gave me a code of p0420.Do u have any suggestions on this code?And what can I do about it?I don't have any money and I need my vehicle.Can you buy anything to help clean it?Help!!!!

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P0420 GMC - Catalyst System Low Efficiency Bank 1 ' Add Comment
Possible causes
- Three way catalyst converter Bank 1
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Powertrain Control Module (PCM)
What does this mean?
Tech notes
As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.
What does this mean?
When is the code detected?
If a condition exists which causes the Powertrain Control Module (PCM) to detect excessive Bank 1 HO2S #2 activity outside of an acceptable range for an extended period of time, the PCM will set the P0420 code. This indicates that the three-way catalytic converters oxygen storage capacity is below a threshold considered acceptable.
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0420 GMC Description
In order to maintain a reasonably low emissions of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), the engine controls system uses a three-way catalytic converter. The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas. This reaction converts them into harmless water vapor and Carbon Dioxide. The catalyst also reduces NOx, converting it to Nitrogen. The Powertrain Control Module (PCM) monitors this process using Bank 1 HO2S #2. Bank 1 HO2S #2, located in the exhaust stream past the three-way catalytic converter, produces an output signal which indicates the oxygen storage capacity of the catalyst. This determines the catalysts ability to convert exhaust emissions effectively. If the catalyst is functioning correctly, the Bank 1 HO2S #2 signal will be far less active than that produced by Bank 1 HO2S #1.

Posted on Mar 31, 2015

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Posted on Jan 02, 2017

  • 2039 Answers

SOURCE: check engine!

normally you need to change the converter if you have smog test you have no choise if not disconnect the battery for a minute and try it out hopefully it will not come back hope its a fixya thanks for the post pierre

Posted on Jul 31, 2008

old marine
  • 1919 Answers

SOURCE: 2001 gmc yukon xl 1500

Check to see if the power steering pump is still turning. If you have a broken drive belt (serpentine belt or "fan" belt), and the pump doesn't turn, you have no power assist. If the pump is still turning, check the fluid level in the reservoir.

Posted on Oct 31, 2008

frcs68
  • 1605 Answers

SOURCE: 2002 YUKON DANALI XL I THINK I RAN OUT OF GAS

try to put 2 gal of gas.
if you run out of gas, the system require little more than a gal of gas to get from the pump in the tank through the filter to the injector. Approximately 1gal just to pressured the fuel rail.

Posted on Apr 07, 2009

JJ_Barricade
  • 11 Answers

SOURCE: receiving engine code p0420 on my 2005 altima 2.5 s

A p0420 code indicates a Catalytic System efficiency failure, Bank 1.
Basically, the computer is seeing reduced efficiency of the catalytic converter or one of it's components (such as an 02 sensor)

There may be a few root causes, such as a faulty oxygen sensor, faulty coolant temperature sensor, faulty converter, Large exhaust leak, or retarded (slow) timing.

Posted on Nov 30, 2009

  • 3 Answers

SOURCE: 2002 GMC YUKON XL 1500 MOTOR DIES AFTER GOING

Check the fuel cap!! If the vacuum relief is not working it can impede the fuel flow and cause the engine to shut down or not restart after a stop. Waiting usually gives things a chance to stabalize and the engine will restsrt. When this happens again try loosening the cap and see if the engine will restart.....If it restarts immediately, REPLACE the fuel cap..Do Not leave it loose because this will cause other problems. If it is not the fuel cap the problem may be the filter, the fuel pump, or aome other fuel system malfunction.

Posted on Jan 24, 2010

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I have a 2002 yukon xl 1500 slt 5.3.I'm having problems with my abs control module and also a code of p1810.Do u have any suggestions as to what I can do?Help I'm low on cash


Melisssketer,
The P 1810 code is usually the transmission, here are some possible causes;
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1 Answer

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P0420 isnt a misfiring code; this code P0420 is refer at Catalyst System Efficiency Below Threshold (Bank 1).

Feel free to contact us if you need additional details to volve it clicking the link.

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Sam,

I would start with a transmission fliud and filter service.

I would then have the trasnmission checked out by a transmission shop. The transmission most of the time has the direct drum band is starting to go. The shops can rebuild it no problem, This is a very common failure wiith the trasnmission.

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Check engine!


normally you need to change the converter if you have smog test you have no choise if not disconnect the battery for a minute and try it out hopefully it will not come back hope its a fixya thanks for the post pierre

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